T型銲接接頭疲勞壽命評估之研究

Fatigue Life Prediction for a T-Joint Fillet Welds

T型接頭填角銲廣泛運用在船舶工程及結構上，有鑒於銲接殘留應力與銲道幾何不連續是銲接製程中不可避免的，且對T型銲接接頭的疲勞強度有顯著直接的影響。故本文考慮銲接殘留應力對銲接結構疲勞壽命的影響，並以熱彈塑性理論、等效應變理論、有限元素法等理論，建立一套可有效評估銲接接頭疲勞壽命的評估程序，並引用Bhuyan等針對T型接頭填角銲接接頭疲勞試驗之實驗結果，來驗證本文所建立之銲接接頭疲勞壽命評估程序的適用性，驗證結果顯示，本文評估之T型銲接接頭壽命與實驗數據接近，是值得設計者採用的預測方法。 T-joint fillet welds are widely employed in naval engineering and ship structures. Since many of these welding components are subjected to complicated states of stress and strain, due to stress concentrations and welding residual stresses. Therefore, this investigation develops an effective procedure by combining the thermal elastio-plastic theory, effective strain theory and finite element methods to predict fatigue life of weldments. Herein, the fatigue life of T-joint fillet welds is forecast using the proposed procedure. The results from the proposed method are compared with those of Bhuyan's summary experimental data. Comparative results demonstrate that fatigue life estimates made using the novel procedure closely approximate experimental results. It's a worthy prediction method for designers.